TABLES OF SCANTLINGS, SPECIFIC GRAVITIES, &c.
No. I.
Table of the Scantlings of Girders, of Yellow Fir, for different Bearings , from 10 to 36feet; Girders 10 feet apart from middle to middle. See Sect. III. art. 138 to 148.
Length of
Depth
Depth
Depth
Depth
Depth
bearingin feet.
10 inches.
11 inches.
12 inches.
13 inches.
14 inches.
Breadth
Breadth
Breadth
Breadth
Breadth
in inches.
in inches.
in inches.
in inches.
in inches.
10
7i
H
4
31
t) 3'■’4
11
9
6|
5
4*
3!
12
10i
8
6}
5
n
13
Si
6i
5}
4*
14
14!
10}
7|
6}
5}
15
16!
12!
9
7}
6
16
18}
14
10!
»!
7
17
16
ni
9f
8
8f
18
19
17f
19f
13
11
H*
12
9}
...
16
13*
10}
21
22
23
17!
15
12
19i
16!
13
18
14*
19!
15*
25
16!
26
Depth
Depth
Depth
18!
27
19 inches
20 inches.
21 inches.
19}
28
Breadth
Breadth
Breadth
29
in inches.
in inches.
in inches.
30
9}
8J
7!
31
ioi
9
7}
32
ii
9}
SI
33
iif
10
8}
34
12!
10}
9*
35
13*
Hi
10
36
14
12
io!
Depth
Depth
Depth
Depth18 inches.
Length of
15 inches.
16 inches.
17 inches.
bearing in
feet.
Breadth
Breadth
Breadth
Breadth
in inches.
in inches.
in inches.
in inches.
ql
4
If
1*
H
10
2f
2!
2
1}
11
H
n
2!
2
12
3f
3
2!
2!
13
41
3!
3
24
14
5
4
3!
3
15
5}
4}
4
3f
16
6!
s*
4!
17
n
6
5
4
18
8
6!
°2
4f
19
9
i 4
6
5*
20
9|
8
6!
5}
21
10}
8}
7!
64
22
H!
9*
8
6!
23
12}
10!
8}
^ 1
2
24
13}
HI
9*
8
25
15
12}
10*
SI
26
16
13
11
9!
27
174
14!
11}
10
2S
18*
15f
12}
10}
29
19}
I6f
17!
13!
14!
HI
12!
30
31
18!
15*
13
32
19}
16!
14
33
—
17*
14}
34
184
15}
35
194
16*
36
To find the scantling for a girder for any length of bearing, look in either the right or left handcolumn for the hearing, and opposite in any of the other columns is the breadth, with the proper depthfor that breadth at the head of the column ; therefore such a breadth and depth may be selected as willbe convenient for the intended purpose. Thus, for a 20 feet bearing a girder may be 16 inches inbreadth, and 12 inches deep; or the breadth may be 13! inches, and the depth 13 inches, and so on ;but where there is space to admit of a deep girder it requires less timber. A new series of depths beginfor bearings above 29 feet.
74 p
This table is calculated by the equation — = b : where l is the length in feet, and b and d the
breadth and depth in inches. The bearing is the distance between the centres of the supporting wallplates ; and the scantlings the least that will answer the purpose.